The CD is a recording medium in which an optically modulated large capacity digital data signal (at maximum 800 Mb) can be stored in a disk having a diameter of about 12 cm. Such CDs include: an audio exclusive-use CDDA which stores digital audio data; a compact disk graphics (CDG) or compact disk enhancement graphics (CDEG) medium for providing lyrics and graphic background pictures as well as audio by storing digital audio data, character data and graphic data therein; a CDV for storing digital audio data together with video data therein; a CD-ROM which can be used as a data base, electronic publication, etc., by storing various data and computer program data therein; and a compact disk interactive (CDI) system for use in multi-media systems by storing audio, video, character and computer program data therein. The physical recording formats of such CDs are based on the recording format of the CDDA. The data recording areas of the CD are largely classified into a lead-in area (LIA), a program area (PMA) and a lead-out area (LOA). In the CDDA, the digital audio data signal is recorded in the PMA, and then program running time and contents information (i.e., a "table of contents") is recorded in the LIA. Thus, the CD reproducer reads the recorded table of contents from the LIA prior to reproduction, and seeks a selected program to reproduce the corresponding program. The LIA consists of eight sub-code channels P, Q, R, S, T, U, V and W. The "table of contents" information utilizes the Q-channel and includes the program number and running time of a maximum of ninety-nine programs. The CDG utilizes R through W sub-code channels which are not used in the CDDA and includes a graphic function for visually displaying lyrics and images corresponding to the songs of a karaoke apparatus. Since such a CDDA or CDG searches the programs of the PMA with reference to the table of contents of the LIA, the number of programs which can be stored in the PMA is limited. For example, since one CD has a maximum capacity of 800Mb, 8,000 still images each having a size of 100 Kb can be recorded thereon. However, table-of-contents information corresponding to 8,000 still images cannot be completely stored in the existing LIA region.
The CD-ROM and CDI reformulate an audio data block comprising 98 frames, which is a data processing unit, into that of a sector unit, in order to record or process the reformulated audio data block (refer to U.S. Pat. No. 4,893,193). A CD-ROM driver is connected to a host computer (a personal computer) and performs a dependent reproduction operation by a CD-ROM operating program which is loaded onto a hard disk or floppy disk of the host computer. Thus, since the CD-ROM should use a particular host computer, compatibility between systems is essential. Accordingly, home distribution of CD-ROM systems is limited. To satisfy the compatibility requirements, a CDI system integrally includes in the CDI reproduction apparatus, the additional elements of a computer, a character reproduction circuit, an audio reproduction circuit and a computer data reproduction circuit. That is, the CDI system is a reproduction exclusive-use computer in which the hard disk or floppy disk of the computer is replaced by the CDI disk. Such a CDI system can access substantial amounts of data only by an application program contained on the disk, which, in terms of its operating system, is very similar to an ordinary personal computer. Accordingly, since the CDI system requires a particular operating system (OS), for example, a CD-RTOS (OS-9/68,000), and application program, the cost is increased due to specific software needs. The computer cannot directly access the data location recorded on the disk, and accordingly, the computer must access the data location via the OS or application program, which is troublesome.
On the other hand, a music video accompaniment apparatus (called a "karaoke" apparatus) displays song lyrics on a monitor while reproducing a musical accompaniment corresponding to the song, whereby users can sing along with the accompaniment by reading the displayed lyrics. Recently, such music video accompaniment apparatuses have been widely distributed, having been placed in music room establishments and in the home as well. Thus far, a laser disk (LD) karaoke apparatus using a laser disk, a computer karaoke apparatus using a semiconductor memory, and a CDG or CDEG karaoke apparatus using the graphics capability of a compact disk have been introduced.
Using a laser disk player, the LD karaoke apparatus reproduces a video signal, an audio signal and a character signal which have been recorded on the LD and displays the reproduced signals on the screen of a video display unit. Here, the audio signal is output through an audio unit. Accordingly, the merits of the LD karaoke apparatus include a high-quality picture and sound, and provisions for a background picture befitting the mood of the song, and lyrics which can be displayed as a motion picture.
However, as the LD (having a diameter of 30 cm) contains massive amounts of motion picture data together with the audio, the disk size is larger than that of the CD (whose diameter is 12 cm), and the number of programs which one laser disk can contain is limited to about 30 video-accompanied songs of average length. Thus, to furnish programs for 2,000 songs requires almost 70 laser disks, and since the price of one LD is still costly, purchasing such disks is burdensome. Also, since the disk is frequently changed according to music selection, a music room establishment should keep an attendant on duty or install an LD changing apparatus which is expensive. Also, due to the immensity of such an LD changing apparatus, considerable installation space is occupied. Moreover, the search speed is slow.
The CDG karaoke apparatus is an apparatus for simultaneously generating the video picture, lyrics and music by reproducing a CDG disk containing still images and character data in the graphic sub-coding channel of the CD. Such apparatuses have recently become popular for home use because CDs are smaller and cheaper than LDs. However, the picture quality of the CDG system is worse than that for LD usage with respect to the representation of a motion picture. Furthermore, since one disk for the conventional CDG system can contains only about 15 songs, a large number of such disks (approximately double) are required to match the capability of an LD system, which also increases the need for the above-mentioned disk-changing apparatus.
The computer karaoke apparatus utilizes a semiconductor memory device and stores song accompaniment data and lyrics data therein in the form of musical instrument digital interface (MIDI) data. Then, corresponding MIDI data is read out according to a song selection, and character data is displayed on a screen of the video display unit. Here, the song accompaniment data is output via an audio processor.
Such a computer karaoke apparatus records the song accompaniment data as MIDI data, differently from the recording method of the audio sampling data of the disk karaoke apparatus. Accordingly, various programs can be recorded, numbering approximately 1,000-1,500 songs. The computer karaoke apparatus can perform high-speed search operations according to the CPU's direct selection of a song, without changing the disk. However, displayed images corresponding to the song cannot be provided, as in the case of the disk karaoke apparatus. Also, sound quality is lower and, when increasing the number of songs for selection, memory capacity should be expanded, which further increases consumer expense. Also, the memory is incompatible with other media, such that programs cannot be easily moved between respective forms of data storage, differently from the medium having a shape of a disk.
As described above, the conventional music video accompaniment apparatuses all have drawbacks as well as merits, and their prices are still high. Accordingly, homes use of these apparatuses has not been greatly expanded.